--8<--
> John tells me that there are serine proteases with completely different
> folds but with very similar active site geometry but that this is
> considered to have occured due to convergent rather than divergent
> evolution.
-->8--
There are two major families in this class, the mammalian trypsin family
and the bacterial subtilisins, which have very similar active sites, but
which "..are not otherwise *detectably* related, and provide one of the
most striking examples of *apparent* evolutionary convergence" (my
asterisks)- from "Proteins", Creighton. In Branden and Tooze it is
described as "a classical example of convergent evolution at the molecular
level".
I seem to remember reading/hearing somewhere that there may be evidence
that the two families share a common ancestor with this active site... am
I remembering correctly? Can anyone offer any insight?
John Walshaw